As digital technology develops, the demands on storage capacity and reliability are increasing and a single storage device (such as a disk) can no longer satisfy the needs. At present, a storage system including a plurality of storage devices has been already developed such as a Redundant Array of Independent Disks (RAID) so as to improve capacity and reliability of data storage. RAID is a data storage virtualization technique, which combines a plurality of physical disk drives into a single logic unit to improve data redundancy, enhance data integration and advance fault tolerance and the like. In such a storage system, when one or more disks therein break down, the fault disk(s) may be detected and it is possible to recover the desired data from other disks in normal operation.